1. Field of the Invention
The present invention generally relates to a method and a network apparatus and, more particularly, to a method and an apparatus for reducing power consumption in a network linking system. The apparatus comprises a network linking interface device, a driving device and a load monitoring module such that the load of the network can be monitored, the average load of the network within a predetermined time interval can be evaluated, the network parameters can be adjusted according to the average load, and thus the network link speed can be re-negotiated properly.
2. Description of the Prior Art
In recent years, with the high development in information-related industries, people have increasing needs for a higher operation speed as well as a higher data transmission rate on the network. In view of this, the industries have made lots of efforts to improve the data transmission rate on the network. For example, the early Ethernet providing a transmission link speed of 10 Mbps (mega bits per second) has been improved as the modern-day enhanced Ethernet providing a transmission link speed of 100 Mbps or even up to 1000 Mbps, i.e., 1 Gbps (giga bits per second).
To operate in coordination with the upgraded transmission rate of the network as well as the compatibility between the product specifications, some manufacturers have proposed various solutions. Please refer to, for example, FIG. 1, which is a block diagram schematically illustrating the configuration of a conventional network interface card (NIC). In FIG. 1, a computer 10 to be linked to the network comprises a network interface card 12, which includes: a media access controller (MAC) 121; an oscillator 125; a gigabit physical layer (gigabit PHY) 123; and a connector 127, through which the computer 10 can be linked to the Ethernet 14 by a network cable. The gigabit physical layer 123 provides linking for three different link speeds, including 10 Mbps, 100 Mbps and 1 Gbps, and performs data transmission on the network at a proper link speed according to the information and settings by negotiating with a remote-end network interface card.
When the network interface card 12 operates at a link speed of 1 Gbps, the gigabit physical layer 123 utilizes a phase-locked loop to multiply a 25-MHz clock signal from the oscillator 125 to be 125-MHz to serve as a system clock in the physical layer. In other words, all the operation modules in the physical layer operate at 125 MHz. On the other hand, if the selected link speed is 100 Mbps, the operation modules in the physical layer operates utilizes the 25-MHz clock signal provide by the oscillator 125 to operate at 25 MHz. Furthermore, when the network interface card 12 operates at a link speed of 10 MHz, the system clock in the physical layer is 2.5 MHz and the operation modules in the physical layer operate at 2.5 MHz. Therefore, the power consumption may varies according to the different operation clocks due to the three different link speeds. Based on the experimental results, the power consumption ratio indicating the comparison among different link speeds including 10 Mbps, 100 Mbps and 1 Gbps is 1:1.2:3. Evidently, the power consumption of linking at 1 Gbps is much larger than the other two cases.
For conventional network linking, after the network interface card is linked at a certain link speed, the fixed link speed is utilized until the linking is terminated. However, the data flow rate is not steady and the load may vary. It wastes of power when the network operates at a higher link speed under low data load.
Therefore, there is a need for reducing power consumption in network linking systems.